check for multiple Array.includes using or

Question

How do I test for multiple .includes with Array.includes() in my if statement? The below seems to work on one item, ie. slug-title-one but ignores the second.

if (item.slug.includes('slug-title-one' || 'slug-title-13')) {
     // checks for and displays if either

}

Instead of using includes, I'd go with the solution in https://stackoverflow.com/questions/16312528/check-if-an-array-contains-any-element-of-another-array-in-javascript — dskow, Dec 14 '17 at 00:17
Because `||` evaluates the first string as truthy and so that is what is passed to `includes()`. You have to check both separately. Read the documentation for includes() — charlietfl, Dec 14 '17 at 00:30
using reduce `['slug-title-one','slug-title-13'].reduce( (a, b) => a && item.slug.includes(b), true)` — 11thdimension, Dec 14 '17 at 00:49

score 9 · Accepted Answer · answered Dec 14 '17 at 00:44

9

As the documentation the Array.includes can only test for a single element.

You could reverse your logic though and use

if (['slug-title-one','slug-title-13'].some(slug => item.slug.includes(slug))) {
     // checks for and displays if either

}

answered Dec 14 '17 at 00:44

Gabriele Petrioli

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Hey, thanks but still on occasion this responds with 'Uncaught TypeError: Cannot read property 'includes' of null' – Dr Upvote Dec 15 '17 at 00:46
@Billy that means that the `item.slug` is `null`. – Gabriele Petrioli Dec 15 '17 at 07:41
The problem is sometimes it will be null, but other times not, I don't want the page to break on the rare instances it is null – Dr Upvote Dec 15 '17 at 20:43
1

wrap the whole `if` in another one the does `if (item.slug) {...} `. Btw this problem would exist in your original attempt as well. – Gabriele Petrioli Dec 15 '17 at 21:32

Christian Santos · Answer 2 · 2017-12-14T00:51:28.680

1

You have a few options. Here are some ideas:

Repeat includes

if (item.slug.includes('slug-title-one') || item.slug.includes('slug-title-13')) { ... }

Helper function

if( includes(item.slug, 'slug-title-one', 'slug-title-13') ) { ... }

function includes() {

    var args = Array.prototype.slice.call(arguments);
    var target = args[0];
    var strs = args.slice(1); // remove first element

    for(var i = 0; i < strs.length; i++) {
        if(target.includes(strs[i])) {
            return true;
        }
    }

    return false;
}

edited Dec 14 '17 at 00:51

answered Dec 14 '17 at 00:32

Christian Santos

5,386
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1

The OP talks about `Array.includes` which means the `item.slug` is an array. So the regex version wouldn't work. – Gabriele Petrioli Dec 14 '17 at 00:40

check for multiple Array.includes using or

2 Answers2